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Comment by acidburnNSA | Hacker News Reader

With seawater uranium extraction getting cheaper by the year and reprocessing still looking like it has all the high costs of remote operation plus perceptions of proliferation risk, and with nuclear not ramping up very quickly due to cheap fracked natural gas that's starting to get exported from the US in bulk, I don't think there's a great reason to reprocess at the moment.

Deep geological waste repositories are fine. Lets get those operating safely so we can answer the "what do you do with the waste" problem definitively and then move on. Reprocessing may make sense again sometime in the future but for now we need the prereq of deep storage. I agree with Frank von Hippel in this case [1].

[1] http://npolicy.org/userfiles/image/The%20Costs%20and%20Benef...

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> I don't think there's a great reason to reprocess at the moment.

At the moment, no. But the economics are likely to change over the next century or so. Which means that reprocessing should definitely be taken into account when determining how long spent fuel needs to be stored. Requiring storage facilities to be good for ten thousand years or more is not reasonable given that it will be economical to reprocess it long, long before then.

With the cost of seawater uranium extraction getting so low I'm really not convinced reprocessing will ever become economical. Doing process stuff at scale in hot cells with remote handling equipment is expensive. Melting down solid fuel into vats makes fission products harder to inventory and track. It's just a pain.

Check out all this seawater extraction progress [1].

[1] https://www.pnnl.gov/news/release.aspx?id=4271

you claim "with cost ... getting so low"

however, neither your link nor anything from a reputable site that i've found through google says anything about costs or current industrial production. do you have any data to back up your claim of low cost, or is that claim purely speculation on your part ?

unless there's data that i've missed, it doesn't sound like seawater extraction is currently economically viable

There is no industrial production; it's in the R&D stage. Current costs are estimated at about 6x uranium mining. Thus, it is not currently economically viable. With R&D, costs are expected to go down. If we go in on nuclear long term, uranium shortages in a few thousand years will make uranium more expensive.

We're comparing long term scenarios here: reprocessing vs. seawater extraction. The reprocessing + hot refabrication process has been done and is extraordinarily expensive. If seawater extraction at scale is indeed viable, it's long term prospects in my view are way better than reprocessing.

https://inis.iaea.org/collection/NCLCollectionStore/_Public/...

Can't you just drag the waste out of long-term storage if you so decide?

Yes, certainly. That's why "long-term" doesn't have to mean "for ten thousand years or more". It only has to mean "until we decide to drag it out again because it's now economical to reprocess it".

how much weight is it? with cheaper launch costs could we get it out of Earth orbit fo less?

The risk of a launch failure causing highly radioactive stuff to rain down on the surface of the earth is just WAY WAY bigger than the risk of some leak in a geological repository in 100k years (when practically all of the truly nasty stuff has long decayed away).

90,000 metric tonnes in the US of high-level waste (incredibly low given that it's produced ~20% of our electricity carbon free for 40 years). You'd have to also launch a bunch of heavy shielding with that just for handling purposes, so be conservative and multiply by 10.

You'd need a really reliable launch process like a space elevator to do this without worrying about dispersing it around in the atmosphere. It's worth talking about but it's hard to imagine a socially-acceptable pathway at the moment. Deep geologic repositories are safe and known. We should just use them.

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